.TH std::filesystem::directory_entry::is_fifo 3 "2024.06.10" "http://cppreference.com" "C++ Standard Libary"
.SH NAME
std::filesystem::directory_entry::is_fifo \- std::filesystem::directory_entry::is_fifo

.SH Synopsis
   bool is_fifo() const;                               \fB(1)\fP \fI(since C++17)\fP
   bool is_fifo( std::error_code& ec ) const noexcept; \fB(2)\fP \fI(since C++17)\fP

   Checks whether the pointed-to object is a FIFO or pipe file. Effectively returns:

   1) std::filesystem::is_fifo(status()).
   2) std::filesystem::is_fifo(status(ec)).

.SH Parameters

   ec - out-parameter for error reporting in the non-throwing overload

.SH Return value

   true if the referred-to filesystem object is a FIFO or pipe file, false otherwise.

.SH Exceptions

   Any overload not marked noexcept may throw std::bad_alloc if memory allocation
   fails.

   1) Throws std::filesystem::filesystem_error on underlying OS API errors, constructed
   with p as the first path argument and the OS error code as the error code argument.
   2) Sets a std::error_code& parameter to the OS API error code if an OS API call
   fails, and executes ec.clear() if no errors occur.

.SH Example


// Run this code

 #include <cstdio>
 #include <cstring>
 #include <filesystem>
 #include <fstream>
 #include <functional>
 #include <iostream>
 #include <memory>
 #include <sys/socket.h>
 #include <sys/stat.h>
 #include <sys/un.h>
 #include <unistd.h>

 namespace fs = std::filesystem;

 void print_entry_type(const std::filesystem::directory_entry& entry)
 {
     std::cout << entry.path() << ": ";

     if (!entry.exists())
         std::cout << "does not exist ";
     if (entry.is_block_file())
         std::cout << "is a block device ";
     if (entry.is_character_file())
         std::cout << "is a character device ";
     if (entry.is_directory())
         std::cout << "is a directory ";
     if (entry.is_fifo())
         std::cout << "is a named IPC pipe ";
     if (entry.is_regular_file())
         std::cout << "is a regular file ";
     if (entry.is_socket())
         std::cout << "is a named IPC socket ";
     if (entry.is_symlink())
         std::cout << "(a symlink)";
     if (entry.is_other())
         std::cout << "(an `other` file)";

     std::cout << '\\n';
 }

 template<typename Type, typename Fun>
 class scoped_cleanup
 {
     std::unique_ptr<Type, std::function<void(const Type*)>> u;

 public:
     scoped_cleanup(Type* ptr, Fun fun) : u{ptr, std::move(fun)} {}
 };

 int main()
 {
     // Create files of different kinds.
     std::filesystem::current_path(fs::temp_directory_path());
     const std::filesystem::path sandbox{"sandbox"};
     scoped_cleanup remove_all_at_exit{&sandbox, [](const fs::path* p)
     {
         std::cout << "cleanup: remove_all(" << *p << ")\\n";
         fs::remove_all(*p);
     }};
     std::filesystem::create_directory(sandbox);
     std::ofstream{sandbox/"file"}; // Creates a regular file
     std::filesystem::create_directory(sandbox/"dir");

     mkfifo((sandbox/"pipe").string().data(), 0644);
     struct sockaddr_un addr; addr.sun_family = AF_UNIX;

     std::strcpy(addr.sun_path, (sandbox/"sock").string().data());
     int fd{socket(PF_UNIX, SOCK_STREAM, 0)};
     scoped_cleanup close_socket_at_exit{&fd, [](const int* f)
     {
         std::cout << "cleanup: close socket #" << *f << '\\n';
         close(*f);
     }};
     bind(fd, reinterpret_cast<sockaddr*>(std::addressof(addr)), sizeof addr);

     fs::create_symlink("file", sandbox/"symlink");

     for (std::filesystem::directory_entry entry: fs::directory_iterator(sandbox))
         print_entry_type(entry);

     // Request file system objects status directly:
     for (const char* str : {"/dev/null", "/dev/cpu", "/usr/include/c++",
                             "/usr/include/asm", "/usr/include/time.h"})
         print_entry_type(fs::directory_entry{str});

 } // Cleanup via scoped_cleanup objects

.SH Possible output:

 "sandbox/symlink": is a regular file (a symlink)
 "sandbox/sock": is a named IPC socket (an `other` file)
 "sandbox/pipe": is a named IPC pipe (an `other` file)
 "sandbox/dir": is a directory
 "sandbox/file": is a regular file
 "/dev/null": is a character device (an `other` file)
 "/dev/cpu": does not exist
 "/usr/include/c++": is a directory
 "/usr/include/asm": is a directory (a symlink)
 "/usr/include/time.h": is a regular file
 cleanup: close socket #3
 cleanup: remove_all("sandbox")

.SH See also

   is_fifo checks whether the given path refers to a named pipe
   \fI(C++17)\fP \fI(function)\fP
